Projectile.



T. A. FIDJELAND. PBOJEGTILE.

APPLICATION FILED JULY 11, 1912.

. 75 202- Patented Oct. 7,1913.

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TERJE AANENSEN FIDJELAND, OF FQSTVEDT, IVELAND, NEAR CHRISTIANSAND, NORWAY.

PIROJE GTILE.

Specification of Letters Patent.

Patented Oct. 7, 1913.

Application filed July 11, 1912. Serial No. 708,784,

To (1% whom it may concern:

Be it known that I, TERJE AANENSEN FIDJELAND, gun'maker, subject of Norway, residing at F ostvedt, Iveland, near Chris- 'tiansand, Norway, have invented new and increase the range and the accuracy of firing. Projectiles of this kind, however, have not.

as yet been practically used to any great extent, because aside from the advantage of the partial elimination of the reactive suction, they have had a series of draw-backs which will be mentioned hereinafter before describing the present invention.

A projectile having both ends pointed, has

heretofore usually been made as a jacket projectile. In these, however, as is we1l known, it is always difficult to make the point of gravity coincide exactly with the central axis of the projectile. As soon as the projectile has left the weapon, it will, even with an exceedingly slight eccentricity of the point of gravity, begin to oscillate. Said oscillations, which correspond to the nutation of the axis of the earth, are so precessional motion, they are not regular, but quite contrary thereto vary with each shot. That even with a fraction of a millimeter of eccentricity of the point of gravity, said oscillations may bring about quite a considerable disturbance, will easily be understood, considering that during flight a projectile performs 2500 to 3000 revolutions per second.

To obtain an effective reduction of the,

reactive suction, the condition therefore is that the axis of the projectile should always coincide with the tangent of trajectory whereby the surface, on which the resistance of the air acts, will be as small as possible. In the ordinary long projectiles this, how.- ever, has not heretofore been possible. On account of the rotation the axis ofthe proj cctile is liable to maintain itself parallel to the initial direction (similarly to a gyroscope). The result hereof is that the-surface ofi'ering resistance to the air and which, at the moment the projectile leaves the barrel,

practically coincides with the maximum cross-sectional area of the projectile will constantly increase. Nor does at the same time, however, the center of action of the resistance of the air coincide with the point of gravity of the projectile, but is located somewhat in front of the same. The point of the projectile will therefore be raised and the projectile will have a tendency to tilt. This, however, will be counteracted by the rotation so that instead thereof there will be a deviation and then, in its turn, a depression of the point of the projectile and so on (the precessional motion).

The present invention has for its objectto reduce the disturbing and irregular movement of projectiles pointed at both ends. This is attained by the facts: a. that the projectile body is made entirely homo-geneous, consisting, for instance, of one integral piece of copper without a jacket. 6. .that

the projectile has a perfectly symmetrical.

shape longitudinally as well as cross-sectionally. c. that the projectile has a comparatively long symmetrical middle portion of a somewhat reduced diameter,

- Such a projectile is illustrated in the accompanying drawing, which shows the projectile partly in outside view and partly in longitudinal section.

1 is the rear pointed end and 2'-' the foremost; both are of symmetrical shape. They are connected together througha long cylindrical middle portion ,3, and all three parts constitute one integral piece, which is homogeneous throughout.

On account of the homogeneous construction of the projectile, it is now possible in contradistinction to the ordinary jacket projectiles, to makethe point of gravity 4 to be located with certainty in the axis I-I of the projectile whereby the objectionable oscillations are for the greater part avoided. when in addition hereto a projectile pointed at both ends is made of a symmetrical shape longitudinally as well as at the same time cross-sectionally, as shown it is thereby attained that the point of action of the re sistance of the air will practically coincide with the point .of gravity. Thereby the raising of the foremost point 2 of the projectile as well as the lateral deviation of the point mentioned in the preamble will be avoided, excepting the trifle caused by the socalled poisson-eflect and Magnuseffect. On the other hand this form of projectile results in, as mentioned above, that the axis would remain parallel to itself which would entail a constant increase of the range as well as a reduction of the accuracy in firing. When, on the other hand, to the above features (a) and (b) is added the feature mentioned under so that the projectile is given the pointed shape illustrated in the drawing, the surface offering resistance to the air will remain symmetrical with respect to the point of gravity. As now, however, there will be presented an increased resistance to the passage of the air pastthe rear collar on to the rear tapering surface at the end of the middle cylindrical portion -3- of the projectile, the point of action of the resultant of the resistance of the air will be displaced behind the point of gravity of the projectile say at the place 6 thereby forcing the foremost point 2 of the projectile downwardly so that the projectile 'will have a tendency to follow the tangent of the trajectory. This result may be entirely obtained by a suitable choice of the dimensions of the projectile relatively to the muzzle velocity and to the pitch of the rifling grooves of the barrel. The precessional motion caused by the resistance of the air will therefore be sli ht, and as the poissonefi'ect and agnus-efiect tend to counteract each other, the oscillations of the projectile will also be slight. It is thus attained that the surface offering resistance to the air will, during the entire flight of the projectile, be as small as possible for which reason the range will also be greater. At the same time it is not till now that the pointed shape of the rear end of the proectile will be of fullefiect which likewise tends to increase the range.

The transversely extending lines shown in the drawing at 7 constitute in a known manner guide portions which are spaced apart by a comparatively long interval. They will thereby prevent any tendency of the projectile to assume an inclined position in the barrel of the gun and with certainty cause the axis of the projectile, on leaving the barrel, to co-incide exactly with the tangent of the trajectory.

Claim- A projectile .consisting of two conoidally pointed symmetricend portions (1, 2) and a long cylindrical middle portion (3) of a diameter somewhat less than the base of said end portions, all three parts constituting one single homogeneous piece of a symmetrical shape longitudinally as Well as cross-sectionally.

In testimony whereof I have signed my' name to this specification in the presence of two subscribing witnesses.

TERJE AANENSEN FIDJELAND.

Witnesses:

WILLIAM BERGMANN, JULIANE BERGMANN. 

